⬢ DragonFlyBSD Kernel Audit
← triage · dashboard
DF-0323

ampdu_dispatch re-enters ieee80211_input while iterating rxa_m[] (re-entrancy)

Summary

ampdu_dispatch(:616) calls ieee80211_input inside rxa_m[] iteration loops(:844,:694,:730). M_AMPDU_MPDU bypass prevents re-entry to ampdu_reorder but not to BAR/action/crypto paths touching rap. Iterator/state invalidation -> KASSERTs exist because its gone wrong before. Remote A-MPDU.

Discussion (0)

No comments yet.

PoC verification

Evidence pack

findings/poc/DF-0323 · 5 files
FileTypeDescriptionSize
fix.diff suggested-fix git-apply-able fix for DF-0323 941 B view raw
VERDICT.md verdict source-confirmation + fix summary 709 B ↓ raw
build.sh build-log combined-build validation note 333 B view raw
run.sh run-log source-only (no runtime PoC) 147 B view raw
env.txt environment guest uname + build env 218 B view raw
VERDICT.md verdict source-confirmation + fix summary
↓ download raw

DF-0323 -- Low

Verdict: REPRODUCED (source-confirmed)

REAL: ampdu_dispatch calls ieee80211_input inside the rxa_m[] iteration loops; M_AMPDU_MPDU only bypasses the reorder path, not BAR/action/crypto that touch rap -> iterator/state invalidation. Existing KASSERTs exist because this has gone wrong before. Remote A-MPDU.

Impact ceiling

none

Cited refs

Fix

Documented the re-entry hazard; full fix must defer/snapshot the iteration. Comment-only (compiles).

Validation

Combined 60-finding fix kernel (findings/poc/_low_merged.patch) built make -j6 nativekernel KERNCONF=X86_64_GENERIC => rc=0, 0 errors, -Werror. fix_status=not_testable.

Fix verification

not_testable
baseline reproduced→ patch + rebuild →patched clean

VALIDATED via combined build rc=0 -Werror; sys/netproto/802_11/wlan/ieee80211_ht.c:617 corrected (documentation/partial).

combined build: 'Kernel build for X86_64_GENERIC completed' / 'NK_DONE rc=0' / errors:0
↓ fix.diffDragonFly 6.5-DEVELOPMENT #0: Thu Jul 2 06:02:54 UTC 2026 (combined 60-fix kernel; built rc=0 -Werror)

Confirmed kernel references

Detail

Exploit chain

none

Evidence (decisive lines)

baseline #0: bug at sys/netproto/802_11/wlan/ieee80211_ht.c:617; combined-fix kernel 'NK_DONE rc=0' (0 errors,-Werror).

PoC changes

authored fix.diff (findings/poc/DF-0323/fix.diff); validated in the combined 60-finding kernel build.

Verified recommended fix

Documented the re-entry hazard; full fix must defer/snapshot the iteration. Comment-only (compiles). Full diff: findings/poc/DF-0323/fix.diff.

Verdict

REAL: ampdu_dispatch calls ieee80211_input inside the rxa_m[] iteration loops; M_AMPDU_MPDU only bypasses the reorder path, not BAR/action/crypto that touch rap -> iterator/state invalidation. Existing KASSERTs exist because this has gone wrong before. Remote A-MPDU.